Laundry Treatment Machine And A Sensor For Sensing the Quality of Water Therefor

ABSTRACT

A wash water sensing apparatus of a laundry treatment machine is provided. The wash water sensing apparatus includes a sealing cover coupled to the tub by being inserted into a hole of the tub, the sealing cover including a through hole; and a sensor body including a plurality of electrodes for measuring the conductivity of wash water and coupled to the sealing cover by being inserted into the through hole. Therefore, it is possible to simplify the structure of a laundry treatment machine and facilitate the assembly of a laundry treatment machine.

TECHNICAL FIELD

The present invention relates to a laundry treatment machine and a wash water sensing apparatus of the laundry treatment machine, and more particularly, to a wash water sensing apparatus of a laundry treatment machine which has a simple structure and is easy to install in a laundry treatment machine.

BACKGROUND ART

Laundry treatment machines are classified into a washing machine removing dust or dirt from clothes or bedclothes by using water and detergent and using mechanical operations, a dryer drying wet laundry by using a dry, hot wind generated by a heater and using mechanical operations, and a combination washer dryer performing both a washing function and a drying function.

A washing machine may include a cabinet forming the exterior of the laundry treatment machine, a washing tub in which laundry is washed, a driving unit rotating the washing tub, a water supply device supplying wash water into the washing tub, and a drain device discharging wash water from the washing tub.

The washing machine may also include an electrode sensor measuring the quality of wash water in the washing tub. The electrode sensor may include a housing filled with a waterproof material, a plurality of electrodes inserted in the housing and a cover coupled to the housing.

The electrode sensor may be coupled and fixed to the exterior of a lower part of the washing machine by coupling elements such as bolts.

However, since coupling elements such as bolts are required to couple the electrode sensor to the washing machine, it takes time and effort to assemble the washing machine, and an additional sealing operation for preventing a leakage of water through the connection between the washing tub and the electrode sensor is required.

DISCLOSURE

1. Technical Problem

The present invention provides a wash water sensing apparatus of a laundry treatment machine, which is easy to assemble and install in a laundry treatment machine and can thus contribute to the reduction of the manufacturing cost of a laundry treatment machine.

2. Technical Solution

According to an aspect of the present invention, there is provided a wash water sensing apparatus including a sealing cover coupled to the tub by being inserted into a hole of the tub, the sealing cover including a through hole; and a sensor body including a plurality of electrodes for measuring the conductivity of wash water and coupled to the sealing cover by being inserted into the through hole. Therefore, it is possible to simplify the structure of a laundry treatment machine and facilitate the assembly of a laundry treatment machine.

ADVANTAGEOUS EFFECTS

The wash water sensing apparatus according to the present invention includes a sealing cover coupled to the tub by being inserted into a hole of the tub, the sealing cover including a through hole; and a sensor body including a plurality of electrodes and coupled to the sealing cover by being inserted into the through hole. Thus, according to the present invention, it is possible to simplify the structure of a laundry treatment machine and facilitate the assembly of a laundry treatment machine. In addition, since the sealing cover is pressed into the tub and the sensor body is pressed into the sealing cover, it is possible to effectively seal the connection between the tub and the sealing cover and the connection between the sealing cover and the sensor body.

The wash water sensing apparatus according to the present invention may include at least three electrodes. Thus, it is possible to precisely determine the amount of detergent by selectively using the three electrodes according to the concentration of detergent. In addition, there is no need to use different electrode sensors for a washing operation and a rinsing operation. That is, only one electrode sensor may be used for both a washing operation and a rinsing operation. Therefore, it is possible to reduce the manufacturing cost of a laundry treatment machine.

The wash water sensing apparatus according to the present invention may include a plurality of electrodes, which are at least partially on a level with the surface of a sensor body and thus do not protrude beyond the sensor body. Therefore, it is possible to prevent foreign materials from being introduced between the electrodes.

The wash water sensing apparatus according to the present invention may include a plurality of electrodes for measuring the conductivity of wash water and an optical sensor for measuring the pollution level of wash water. Thus, it is possible to determine both the conductivity and pollution level of wash water. In addition, it is possible to improve the performance of a laundry treatment machine by appropriately adjusting the duration of a washing process and the temperature of wash water according to the conductivity and pollution level of wash water.

DESCRIPTION OF DRAWINGS

FIG. 1 illustrates a cross-sectional view of a drum-type washing machine having an electrode sensor according to a first exemplary embodiment of the present invention;

FIG. 2 illustrates a cross-sectional view showing how a tub and the electrode sensor shown in FIG. 1 are connected;

FIG. 3 illustrates an exploded lateral view of the electrode sensor shown in FIG. 2;

FIG. 4 illustrates a lateral view of the electrode sensor shown in FIG. 1;

FIG. 5 illustrates a perspective view of the electrode sensor shown in FIG. 2;

FIG. 6 illustrates an exploded perspective view of the electrode sensor shown in FIG. 5;

FIG. 7 illustrates a lateral view of the electrode sensor shown in FIG. 4, as seen from direction A of FIG. 4;

FIG. 8 illustrates a perspective view of an electrode sensor according to a second exemplary embodiment of the present invention;

FIG. 9 illustrates a graph showing the relationship between the concentration of detergent and the voltage of the electrode sensor shown in FIG. 8;

FIG. 10 illustrates a perspective view of an electrode sensor according to a third exemplary embodiment of the present invention;

FIG. 11 illustrates a perspective view of an electrode sensor according to a fourth exemplary embodiment of the present invention;

FIG. 12 illustrates an exploded perspective view of the electrode sensor shown in FIG. 11;

FIG. 13 illustrates a perspective view of an electrode sensor according to a fifth exemplary embodiment of the present invention;

FIG. 14 illustrates a perspective view of an electrode sensor according to a sixth exemplary embodiment of the present invention;

FIG. 15 illustrates a plan view of a sensor body shown in FIG. 14, as seen from direction A of FIG. 14;

FIG. 16 illustrates a plan view of a sensor body of an electrode sensor according to a seventh exemplary embodiment of the present invention;

FIG. 17 illustrates a perspective view of a wash water sensing apparatus according to an eighth exemplary embodiment of the present invention;

FIG. 18 illustrates a plan view of the wash water sensing apparatus shown in FIG. 17, as seen from direction A of FIG. 17;

FIG. 19 illustrates a perspective view of a wash water sensing apparatus according to a ninth exemplary embodiment of the present invention; and

FIG. 20 illustrates a perspective view of a wash water sensing apparatus according to a tenth exemplary embodiment of the present invention.

BEST MODE

The present invention will hereinafter be described more fully with reference to the accompanying drawings, in which exemplary embodiments of the invention are shown.

A laundry treatment machine according to an exemplary embodiment of the present invention will hereinafter be described, taking a drum-type washing machine as an example.

FIG. 1 illustrates a cross-sectional view of a drum-type washing machine 1 having an electrode sensor 150 according to a first exemplary embodiment of the present invention. Referring to FIG. 1, the drum-type washing machine 1 may include a cabinet 2 which forms the exterior of the drum-type washing machine 1; a tub 120 which is installed in the cabinet 2 and can accommodate wash water; a drum 125 which is installed in the tub 120 so as to be rotatable and can accommodate laundry; a motor 8 which is disposed at the rear of the drum 125 and drives the drum 125; a water supply device which supplies water or detergent into the tub 120; and a drain device which discharges wash water from the tub 120.

A base 10 may be installed at the bottom of the cabinet 2. A top cover 12 may be installed at the top of the cabinet 2. A front cover 14 may be installed at the front of the cabinet 2. A door 16 may be installed on the front cover 14 so as to open or close a laundry inlet/outlet hole (not shown).

A control device 18 may be installed on an upper part of the cabinet 2. The control device 18 may manipulate and control the operation of the drum-type washing machine 1.

The water supply device may include a water supply valve 22 which is connected to an external hose 20 and controls the supply of water through the external hose 20; a first water supply hose 26 which guides water supplied through the water supply valve 22 into a detergent box 24; and a second water supply hose 28 which guides wash water, i.e., water mixed with detergent in the detergent box 24, into the tub 120.

The drain device may include a first drain hose 30 which is connected to the tub 120 and discharges wash water from the tub 120; a drain pump 32 which is connected to the first drain hose 30 and pumps wash water; and a second drain hose 34 which guides wash water in the drain pump 32 toward the outside of the cabinet 2.

The electrode sensor 150 may be disposed in the tub 120. The electrode sensor 150 may measure the quality of wash water in the tub 120. The electrode sensor 150 may be disposed at the rear of a lower part of the tub 120. The electrode sensor 150 may be mounted into the tub 120 through a hole 5 a formed on a rear surface 5 of the tub 120.

FIG. 2 illustrates a cross-sectional view showing how the electrode sensor 150 is coupled to the tub 120, FIG. 3 illustrates an exploded lateral view of the electrode sensor 150, FIG. 4 illustrates a lateral view of the electrode sensor 150, FIG. 5 illustrates a perspective view of the electrode sensor 150, FIG. 7 illustrates an exploded perspective view of the electrode sensor 150, and FIG. 7 illustrates a lateral view of the electrode sensor 150, as seen from direction A of FIG. 4.

Referring to FIGS. 2 through 6, the electrode sensor 150 may include a sealing cover 60 and a sensor body 70. The sealing cover 60 may be coupled to the tub 120 by being inserted into the hole 5 a. The sensor body 70 may include a plurality of electrodes 72 and may be coupled to the sealing cover by being inserted into a through hole 61 formed through the sealing cover 60.

The sealing cover 60 may be coupled to the tub 120 by pressing the sensor body 70 into the tub 120. Thus, the sealing cover 60 may be more elastic than the sensor body 70. The sealing cover 60 may be formed of rubber.

The sealing cover 60 may include a cover insertion portion 62 which can be inserted into the hole 5 a. Referring to FIG. 3, when the cover insertion portion 62 is yet to be inserted into the hole 5 a, the cover insertion portion 62 may have an outer diameter d2, which is greater than a diameter d1 of the hole 5 a. For example, the outer diameter d2 may be about 5 mm greater than the diameter d1. On the other hand, referring to FIG. 4, when the cover insertion portion 62 is inserted in the hole 5 a, the cover insertion portion 62 may be pressed by the inner circumferential surface of the hole 5 a, and thus, the outer diameter of the cover insertion portion 62 may be reduced to an outer diameter d2′ which is the same diameter as the diameter d1.

Referring to FIG. 2, the sealing cover 60 may also include first and second ribs 63 and 64. The first and second ribs 63 and 64 may fix the sealing cover 60 into the hole 5 a at the front and the rear, respectively, of a rear surface 5 of the tub 120 when the sealing cover 60 is coupled to the tub 120. More specifically, the first and second ribs 63 and 64 may protrude radially from the cover insertion portion 62. The first and second ribs 63 and 64 may be a predetermined distance apart from each other. Due to the first and second ribs 63 and 64, the cover insertion portion 62 of the sealing cover 60 may be fit in the hole 5 a when the sealing cover 60 is inserted in the hole 5 a.

Referring to FIG. 4, a surface 64 a of the second rib 64 may be placed in contact with the rear surface 5 of the tub 120 when the sealing cover 60 is inserted into the hole 5 a. The surface 64 a of the second rib 64 may be recessed toward the centre of the through hole 61.

A hem portion 65 of the sealing cover 60 may be tapered so that the sealing cover 60 can be easily inserted into the hole 5 a.

Referring to FIGS. 5 through 7, the sealing cover 60 may also include a cover cylinder portion 66 which extend backwards from the second rib 64 and a number of hook portions 67 which protrude from the cover cylinder portion 66 so as to be able to be coupled to the sensor body 70. At least one hook portion 67 may be formed on the cover cylinder portion 66. Referring to FIGS. 6 and 7, two hook portions 67 may be formed on opposite sides of the cover cylinder portion 66.

The sensor body 70 may be formed through injection molding, and the electrodes 72 may be inserted into the sensor body 70 during the formation of the sensor body 70. For example, two electrodes 72 may be inserted into the sensor body 70 so that the ends of the two electrodes 72 can be exposed.

The sensor body 70 may include a body insertion portion 73 which can be inserted into the through hole 61 and a body cylinder portion 74 which extends backwards from the body insertion portion 73.

Referring to FIG. 3, when the body insertion portion 73 is yet to be inserted into the through hole 61, the body insertion portion 73 may have an outer diameter d4 which is greater than a diameter d3 of the through hole 61. For example, the outer diameter d4 may be about 2 mm greater than the diameter d3. On the other hand, referring to FIG. 4, when the body insertion portion 73 is inserted into the through hole 61, the inner circumferential surface of the through hole 61 may be pressed by the body insertion portion 73, and thus, the diameter of the through hole 61 may be reduced to a diameter d3?which is the same as the outer diameter d4.

Referring to FIGS. 5 through 7, the sensor body 70 may also include an engaging protrusion 75 which engages with the hook portion 67 when the body insertion portion 73 is inserted into the through hole 61. The engaging protrusion 75 may protrude radially from a portion of the body insertion portion 74 corresponding to the hook portions 67. The body cylinder portion 74 may include a plurality of recessed portions 74 a into which the hook portions 67 can be inserted.

How to assemble the electrode sensor 150 will hereinafter be described in detail.

The sealing cover 60 may be pressed into the hole 5 a of the tub 120. Since the sealing cover 60 is formed of rubber and the outer diameter of the cover insertion portion 61 is greater than the diameter of the insertion hole 5 a when the cover insertion portion 61 is yet to be inserted into the hole 5 a, the cover insertion portion 61 may be pressed by and thus firmly attached onto the inner circumferential surface of the hole 5 a when the sealing cover 60 is inserted into the hole 5 a.

Therefore, it is possible to easily install the sealing cover 60 simply by inserting the sealing cover 60 into the hole 5 a of the tub 120. In addition, since the cover insertion portion 62 is pressed by and thus firmly attached onto the inner circumferential surface of the hole 5 a when the sealing cover 60 is inserted into the hole 5 a, there is no need to additionally seal the connection between the sealing cover 60 and the hole 5 a.

Once the installation of the sealing cover 60 is complete, the sensor body 70 may be inserted into the through hole 61 of the sealing cover 60. Since the outer diameter of the body insertion portion 73 is greater than the diameter of the through hole 61 when the sensor body 70 is yet to be inserted into the through hole 61, the body insertion portion 73 may be pressed by and thus firmly attached onto the inner circumferential surface of the through hole 61 when the sensor body 70 is inserted into the through hole 61.

Therefore, it is possible to easily assemble the electrode sensor 150 simply by inserting the sensor body 70 into the through hole 61 of the sealing cover 60. In addition, since the body insertion portion 73 of the sensor body 70 is pressed by and thus firmly attached onto the inner circumferential surface of the hole 5 a when the sensor body 70 is inserted into the through hole 61 of the sealing cover 60, there is no need to additionally seal the connection between the sealing cover 60 and the hole 5 a.

The operation of the electrode sensor 150 will hereinafter be described in detail.

When laundry is loaded into the drum 125 and wash water is supplied into the tub 120, the electrode sensor 150 measures the conductivity of the wash water in the tub 120.

More specifically, if a voltage is applied to the electrodes 72 of the electrode sensor 150, the electrodes 72 may be electrically connected, and thus, the electrode sensor 150 may thus be able to measure the conductivity of the wash water in the tub 120.

FIG. 8 illustrates a perspective view of an electrode sensor 80 according to a second exemplary embodiment of the present invention. Referring to FIG. 8, the electrode sensor 80 may include a sealing cover 84, which is coupled to the tub 120 by being inserted into the hole 5 a of the tub 120, and a sensor body 86, which is coupled to the sealing cover 84 by being inserted into a through hole of the sealing cover 84 and includes first through third electrode sensors 81 through 83. The second exemplary embodiment is almost the same as the first exemplary embodiment except that the electrode sensor 80 includes at least three electrodes and that at least one of the three electrodes has a different length from the other electrodes. Thus, the second exemplary embodiment will hereinafter be described, focusing mainly on differences with the first exemplary embodiment.

The first and second electrodes 81 and 82 may have the same length, and the third electrode 83 may be shorter than the first and second electrodes 81 and 82.

The operation of the electrode sensor 80 will hereinafter be described in detail.

FIG. 9 illustrates a graph showing the relationship between the concentration of detergent and the voltage of the electrode sensor 80. Referring to FIG. 9, when a current is applied to the electrode sensor 80, the concentration of detergent may serve as a resistor. That is, the higher the concentration of detergent, the lower the voltage of each of the first through third electrodes 81, 82 and 83 becomes. The more the voltage of an electrode varies according to the concentration of detergent (i.e., the greater the slope of a voltage-detergent concentration curve of an electrode), the better the electrode is able to precisely determine the amount of detergent.

Any two of the first through third electrodes 81 through 83 producing a greatest voltage variation for a given detergent concentration variation may be selectively used. The amount by which the voltage of each of the first through third electrodes 81 through 83 varies according to the concentration of detergent may differ from a first concentration section S1 to a second concentration section S2.

The first concentration section S1 may correspond to a period of time during which there is little, if any, detergent detected, i.e., a period of time during which a rinsing operation is performed. The second concentration section S2 may correspond to a period of time during which a wash operation is performed alone or together with a rinsing operation.

During the first concentration section S1, the first and second electrodes 81 and 82 may produce a greatest voltage variation for any given detergent concentration variation. More specifically, there is little, if any, detergent detected during the first concentration section S1. In addition, since the first and second electrodes 81 and 82 are longer than the third electrode 83, the contact area between each of the first and second electrodes 81 and 82 and wash water is larger than the contact area between the third electrode 83 and the wash water. Thus, during the first concentration section S1, the first and second electrodes 81 and 82 may be selectively used to detect the amount of detergent.

On the other hand, during the second concentration section S2, the third electrode 83 and one of the first and second electrodes 81 and 82 may produce first a greatest voltage variation for any given detergent concentration variation. More specifically, the amount of detergent is greater during the second concentration section S2 than during the first concentration section S1. Thus, during the second concentration section S1, the third electrode 83 and one of the first and second electrodes 81 and 82 (particularly, the first electrode 81) may be selectively used to detect the amount of detergent.

Therefore, during the first concentration section S1, a current may be applied to the first and second electrodes 81 and 82, and thus, the amount of detergent may be determined based on voltage measurements obtained from the first and second electrodes 81 and 82. On the other hand, during the second concentration section S2, a current may be applied to the first and third electrodes 81 and 83, and thus, the amount of detergent may be determined based on voltage measurements obtained from the first and third electrodes 81 and 83. In this manner, it is possible to precisely determine the amount of detergent by selectively using the first through third electrodes 81 through 83 according to the concentration of detergent.

FIG. 10 illustrates a perspective view of an electrode sensor 90 according to a third exemplary embodiment of the present invention. The third exemplary embodiment is almost the same as the second exemplary embodiment except that the electrode sensor 90 includes three electrodes having different lengths. Thus, the third exemplary embodiment will hereinafter be described, focusing mainly on differences with the second exemplary embodiment.

Referring to FIG. 10, the electrode sensor 90 may include fourth through sixth electrodes 91 through 93. The fourth electrode 91 may be shorter than the fifth electrode 92, and the fifth electrode 92 may be shorter than the sixth electrode 93. The fourth through sixth electrodes 91 through 93 may be sequentially arranged in order of length.

The electrode sensor 90 may be able to precisely measure the amount of detergent by selectively using the fourth through sixth electrodes 91 through 93. In addition, the electrode sensor 90 may be able to prevent foreign materials from being stuck between the fourth through sixth electrodes 91 through 93.

FIG. 11 illustrates a perspective view of an electrode sensor 1100 according to a fourth exemplary embodiment of the present invention, and FIG. 12 illustrates an exploded perspective view of the electrode sensor 1100. Referring to FIGS. 11 and 12, the electrode sensor 1100 may include a sealing cover 1103 coupled to the tub 120 and a sensor body 1104 coupled to the sealing cover 1103 and including a plurality of electrodes 1102. At least one of the contact surfaces of wash water in the tub 120 and each of the electrodes 1102 may be disposed on a level with a surface of the sensor body 1104.

More specifically, the electrodes 1102 may be inserted into a body insertion portion 1105 of the sensor body 1104, and at least one surface of each of the electrodes 1102 may be exposed on a front surface 1105 a of the body insertion portion 1105, facing the tub 120.

Each of the electrodes 1102 may include a first portion 1102 a inserted into the body insertion portion 1105 and a second portion 1102 b exposed on the front surface 1105 of the body insertion portion 1105 and contacting wash water in the tub 120.

The area of the second portions 1102 b of the electrodes 1102 may be determined by the thickness of the electrodes 1102. The area of the second portions of the electrodes 1102 may be appropriately adjusted in order to control the performance of the electrode sensor 1100.

The operation of the electrode sensor 1100 will hereinafter be described in detail.

When laundry is loaded into the drum 125 and wash water is supplied into the tub 120, the electrode sensor 1100 measures the conductivity of the wash water in the tub 120.

More specifically, if a voltage is applied to the electrodes 72 of the electrode sensor 150, the voltage of the electrodes 1102 may vary according to the concentration of detergent in the wash water in the tub 120. The electrode sensor 1100 may determine the amount of detergent by measuring the voltage of the electrodes 1102.

Since the electrodes 1102 do not protrude beyond the sensor body 1104, it is possible to prevent foreign materials from being stuck between the electrodes 1102. Therefore, it is possible to prevent deterioration the performance of the electrode sensor 1100 and thus to increase the lifetime of the electrode sensor 1100.

FIG. 13 illustrates a perspective view of an electrode sensor 1110 according to a fifth exemplary embodiment of the present invention. The fifth exemplary embodiment is almost the same as the fourth exemplary embodiment except that an electrode 1112 is attached onto the surface of a sensor body 1114. Thus, the fifth exemplary embodiment will hereinafter be described, focusing mainly on differences with the fourth exemplary embodiment.

Referring to FIG. 13, the electrode 1112 may be attached onto an outer circumferential surface 1115 a of a body insertion portion 1115 of the sensor body 1114. The electrode 1112 may be formed as a plate, but the present invention is not restricted to this. That is, the electrode 1112 may be formed as a stick.

The electrode 1112 may be bonded onto the outer circumferential surface 1115 a of the body insertion portion 1115 by an adhesive. A groove (not shown) for accommodating the electrode 1112 may be formed on the outer circumferential surface 1115 a.

According to the fifth exemplary embodiment, it is possible to increase the contact area between the electrode 1112 and wash water.

FIG. 14 illustrates a perspective view of an electrode sensor 1120 according to a sixth exemplary embodiment of the present invention, and FIG. 15 illustrates a plan view of a sensor body 1121 of the electrode sensor 1120, as seen from direction A of FIG. 14. The sixth exemplary embodiment is almost the same as the fourth exemplary embodiment except that a body insertion portion 1130 of a sensor body 1121 includes first and second protrusions 1131 and 1132, and that first and second electrodes 1141 and 1142 are disposed on the first and second protrusions 1131 and 1132, respectively. Thus, the sixth exemplary embodiment will hereinafter be described, focusing mainly on differences with the fourth exemplary embodiment.

Referring to FIGS. 14 and 15, the first and second protrusions 1131 and 1132 may protrude toward the tub 120. The first and second protrusions 1131 and 1132 may face each other.

A surface 1131 a of the first protrusion 1131 on which the first electrode 1141 is disposed and a surface 1131 a of the second protrusion 1132 on which the second electrode 1142 is disposed may face each other. Thus, the first and second electrodes 1141 and 1142 may face each other. The first and second electrodes 1131 and 1132 may be attached onto or inserted into the first and second protrusions 1131 and 1132, respectively.

The first and second electrodes 1141 and 1142 may be exposed on the surfaces 1131 a of the first and second protrusions 1131 and 1132 and on top surfaces 1131 b and 1132 b of the first and second protrusions 1131 and 1132 and may thus be able to contact wash water.

FIG. 16 illustrates a plan view of a sensor body of an electrode sensor according to a seventh exemplary embodiment of the present invention. The seventh exemplary embodiment is almost the same as the sixth exemplary embodiment except that first and second electrodes 1151 and 1152 are disposed on opposite sides of a sensor body. Thus, the seventh exemplary embodiment will hereinafter be described, focusing mainly on differences with the sixth exemplary embodiment.

More specifically, the first electrode 1151 may be disposed on a surface 1131 c of a first protrusion 1131, and the second electrode 1152 may be disposed on a surface 1132 c of a second protrusion 1132. The surfaces 1131 c and 1132 c may be on opposite sides of the sensor body.

FIG. 17 illustrates a perspective view of a wash water sensing apparatus 1200 according to an eighth exemplary embodiment of the present invention, and FIG. 18 illustrates a plan view of the wash water sensing apparatus 1200, as seen from direction A of FIG. 17. Referring to FIGS. 17 and 18, the wash water sensing apparatus 1200 may include a sealing cover 1201 which is coupled to the tub 120 by being inserted into the hole 5 a of the tub 120; a sensor body 1202 which is coupled to the sealing cover 1201 by being inserted into a through hole of the sealing cover 1201; an optical sensor 1210 which is disposed on one side of the sensor body 1202 and measures the pollution level of wash water; and an electrode sensor 1220 which is disposed on the other side of the sensor body 1202 and measures the conductivity of wash water.

The sealing cover 1201 may be pressed into the tub 120, and the sensor body 1202 may be pressed into the sealing cover 1201. The sealing cover 1201 may be more elastic than the tub 120 or the sensor body 1202. The sealing cover 1201 may be formed of rubber.

The sensor body 1202 may include a body insertion portion 1203 which is formed as a protrusion and can thus be inserted into the sealing cover 1201 and a body connector portion 1204 which extends backwards from the body insertion portion 1203 and to which wires connected to the optical sensor 1220 and the electrode sensor 1210 are coupled.

The body insertion portion 1203 may be cylindrical. The body insertion portion 1203 may include first and second protrusions 1205 and 1206 which protrude toward the tub 120. The first and second protrusions 1205 and 1206 may face each other.

The optical sensor 1210 may include a light emitter 1211 disposed on the first protrusion 1205 and emitting light and a light receptor 1212 disposed on the second protrusion 1206 and receiving the light emitted by the light emitter 1211. A surface of the first protrusion 1205 on which the light emitter 1211 is disposed and a surface of the second protrusion 1206 on which the light receptor 1212 is disposed may face each other.

The electrode sensor 1220 may include first and second electrodes 1221 and 1222. The first and second electrodes 1221 and 1222 may be disposed between the first and second protrusions 1205 and 1206. The sensor body 1202 may be formed through injection molding, and the first and second electrodes 1221 and 1222 may be inserted into the sensor body 1202 during the formation of the sensor body 1202. The first and second electrodes 1221 and 1222 may be a predetermined distance apart from each other.

The operation of the wash water sensing apparatus 1200 will hereinafter be described in detail.

Laundry may be loaded into the drum 125, and wash water mixed with detergent may be supplied into the tub 120. The wash water in the tub 120 may be polluted by dust and dirt from the laundry.

The wash water sensing apparatus 1200 may measure the quality of the wash water in the tub 120.

If the light emitter 1211 of the optical sensor 1210 emits light, the light receptor 1212 of the optical sensor 1210 may receive the light through the wash water in the tub 120. The more polluted the wash water is, the less the amount of light received by the light receptor 121. Therefore, the wash water sensing apparatus 1200 may determine the pollution level of the wash water in the tub 120 based on the amount of light received by the light receptor 1212. Thus, the wash water sensing apparatus 1200 may determine for how long a washing operation is to be performed and how much detergent is to be used in the washing operation based on the pollution level of the wash water in the tub 120.

If a current is applied to the first and second electrodes 1221 and 1222 of the electrode sensor 1220, the voltage of the first and second electrodes 1221 and 1222 may vary according to the concentration of detergent in the wash water in the tub 120. Thus, the wash water sensing apparatus 1200 may determine the amount of detergent in the wash water in the tub 120 based on the voltage of the first and second electrodes 1221 and 1222.

Therefore, it is possible to appropriately adjust the duration of a washing process and the temperature of the wash water in the tub based on measurement data provided by the optical sensor 1210 and the electrode sensor 1220.

That is, if the measurement data provided by the optical sensor 1210 and the electrode sensor 1210 indicates that the pollution level of the wash water in the tub 120 is lower than a reference pollution level, and that the amount of detergent in the wash water in the tub 120 is greater than a reference detergent amount level, the duration of a washing process or the temperature of the wash water in the tub 120 may be reduced. In the latter case, it is possible to reduce the heating energy of a heater and thus to reduce the time and cost required for performing a washing operation.

On the other hand, if the measurement data provided by the optical sensor 1210 and the electrode sensor 1210 indicates that the pollution level of the wash water in the tub 120 is higher than the reference pollution level, and that the amount of detergent in the wash water in the tub 120 is less than the reference detergent amount level, the duration of a washing process or the temperature of the wash water in the tub 120 may be increased.

In this manner, it is possible to improve the performance of a washing operation by appropriately adjusting the duration of a washing process and the temperature of wash water based on the pollution level and conductivity of the wash water.

FIG. 19 illustrates a perspective view of a wash water sensing apparatus 1230 according to a ninth exemplary embodiment of the present invention. The ninth exemplary embodiment is almost the same as the eighth exemplary embodiment except that first and second electrodes 1231 and 1232 of an electrode sensor 1230 are disposed on a level with a surface 1202 a of a sensor body 1202. Thus, the ninth exemplary embodiment will hereinafter be described, focusing mainly on differences with the eighth exemplary embodiment.

Referring to FIG. 19, the electrode sensor 1230 may include the first and second electrodes 1231 and 1232. The first and second electrodes 1231 and 1232 may be disposed between first and second protrusions 1205 and 1206. The first and second electrodes 1231 and 1232 may be inserted in the sensor body 1202 so that at least one surface of each of the first and second electrodes 1231 and 1232 can be exposed on the surface 1202 a of the sensor body 1202. The contact area between wash water and each of the first and second electrodes 1231 and 1232 may be determined by the thickness of the first and second electrodes 1231 and 1232. The thickness of the first and second electrodes 1231 and 1232 may be appropriately adjusted in order to control the performance of the electrode sensor 1230.

Since the first and second electrodes 1231 and 1232 do not protrude beyond the sensor body 1202, it is possible to prevent foreign materials from being stuck between the electrodes 1231 and 1232. Therefore, it is possible to prevent deterioration the performance of the electrode sensor 1230 and the performance of an optical sensor 1210.

FIG. 20 illustrates a perspective view of a wash water sensing apparatus 1240 according to a tenth exemplary embodiment of the present invention. The tenth exemplary embodiment is almost the same as the eighth exemplary embodiment except that first and second electrodes 1241 and 1242 of an electrode sensor 1240 are attached onto a sensor body 1202. Thus, the tenth exemplary embodiment will hereinafter be described, focusing mainly on differences with the eighth exemplary embodiment.

Referring to FIG. 20, the first and second electrodes 1241 and 1242 may be attached onto first and second protrusions 1205 and 1206, respectively. More specifically, the first and second electrodes 1241 and 1242 may be disposed on opposite sides of the sensor body 1202. The first and second electrodes 1241 and 1242 may be formed as plates. A pair of grooves for accommodating the first and second electrodes 1241 and 1242 may be respectively formed on the first and second protrusions 1205 and 1206. 

1. A wash water sensing apparatus of a laundry treatment machine, the wash water sensing apparatus comprising: a sealing cover coupled to a tub by being inserted into a hole of the tub, the sealing cover including a through hole; and a sensor body including a plurality of electrodes for measuring the conductivity of wash water and coupled to the sealing cover by being inserted into the through hole.
 2. The wash water sensing apparatus of claim 1, wherein the sealing cover is more elastic than the sensor body.
 3. The wash water sensing apparatus of claim 1, wherein the sealing cover further includes a cover insertion portion formed so as to be able to be inserted into the hole of the tub and the outer diameter of the cover insertion portion is greater than the diameter of the hole of the tub when the sealing cover is yet to be inserted into the hole of the tub.
 4. The wash water sensing apparatus of claim 1, wherein the sensor body further includes a body insertion portion formed as a protrusion so as to be able to be inserted into the through hole and the outer diameter of the body insertion portion is greater than the diameter of the through hole when the sensor body is yet to be inserted into the through hole.
 5. The wash water sensing apparatus of claim 1, wherein the sensor body is formed through injection molding and the electrodes are inserted into the sensor body during the formation of the sensor body.
 6. The wash water sensing apparatus of claim 1, wherein at least one surface of each of the electrodes is disposed on a level with a surface of the sensor body.
 7. The wash water sensing apparatus of claim 6, wherein the electrodes are inserted into the sensor body so that at least one surface of each of the electrodes can be exposed on the surface of the sensor body.
 8. The wash water sensing apparatus of claim 6, wherein the electrodes are formed as plates so as to be able to be attached onto the sensor body.
 9. The wash water sensing apparatus of claim 6, wherein the sensor body further includes first and second protrusions facing each other and the electrodes include first and second electrodes disposed on the first and second protrusions, respectively.
 10. The wash water sensing apparatus of claim 1, wherein the sensor body includes at least three electrodes, at least one of the three electrodes has a different length from the other electrodes, and at least two of the three electrodes are selectively used to measure the conductivity of wash water in consideration of the concentration of detergent.
 11. The wash water sensing apparatus of claim 10, wherein two of the three electrodes producing a largest voltage variation for a detergent concentration variation are used to measure the conductivity of wash water.
 12. The wash water sensing apparatus of claim 10, wherein a detergent concentration section is divided into a first concentration section and a second concentration section corresponding to a higher detergent concentration than the first concentration section according to the concentration of detergent, the first and second longest electrodes of the three electrodes are used during the first concentration section, and the longest electrode and the shortest electrode of the three electrodes are used during the second concentration section.
 13. The wash water sensing apparatus of claim 10, wherein, during a washing operation, the conductivity of wash water is measured by applying a current to the longest electrode of the three electrodes and the shortest electrode of the three electrodes.
 14. The wash water sensing apparatus of claim 10, wherein, during a rinsing operation, the conductivity of wash water is measured by applying a current to the first and second longest electrodes of the three electrodes.
 15. The wash water sensing apparatus of claim 1, wherein the sensor body further includes an optical sensor measuring the pollution level of wash water.
 16. The wash water sensing apparatus of claim 15, wherein the sensor body also includes first and second protrusions facing each other and the optical sensor includes a light emitter disposed on the first protrusion and emitting light and a light receptor disposed on the second protrusion and receiving the light emitted by the light emitter.
 17. A laundry treatment machine comprising: a tub in which wash water is loaded; a sealing cover coupled to the tub by being inserted into a hole of the tub, the sealing cover including a through hole; and a sensor body including a plurality of electrodes for measuring the conductivity of wash water and coupled to the sealing cover by being inserted into the through hole.
 18. The laundry treatment machine of claim 17, wherein at least one surface of each of the electrodes is disposed on a level with a surface of the sensor body.
 19. The laundry treatment machine of claim 17, wherein the sensor body includes at least three electrodes, at least one of the three electrodes has a different length from the other electrodes, and at least two of the three electrodes are selectively used to measure the conductivity of wash water in consideration of the concentration of detergent.
 20. The laundry treatment machine of claim 17, wherein the sensor body further includes an optical sensor measuring the pollution level of wash water. 